1. Field of the Invention
The present invention relates to an exhaust emission control device for purifying various exhaust gases discharged from internal combustion engines or diesel engines of automotive vehicles, industrial machines or various factory plants.
2. Description of the Prior Art
To avoid air pollution caused by various exhaust gases containing various inflammable and nonflammable fine particles, there have been various exhaust emission control methods and devices for purifying the exhaust gases. In Japanese Patent Laid-open Publication No. 1-159408 there is disclosed one of such exhaust emission control devices which includes a casing arranged above an electric furnace and a ceramic filter element disposed within the casing to collect fine particles from exhaust gases introduced into an inlet opening of the casing and to cause the collected fine particles to fall into the electric furnace. In this device, the ceramic filter element has a thin-walled cellular or honeycomb structure formed with a plurality of axially extending passages which are separated from each other by thin partition walls and closed at opposite ends thereof in an alternating checked pattern.
In such a conventional exhaust emission control device as described above, only a single ceramic filter element is adapted to purify exhaust gases introduced therein. As a result, the gas purifying performance of the device is greatly limited. To enhance the gas purifying performance of the device, it is required to provide a plurality of ceramic filter elements in a limited space.